The celebrated lower Cambrian Chengjiang biota of Yunnan Province, China, represents one of the most significant ever paleontological discoveries. Deposits of ancient mudstone, about 520 million years old, have yielded a spectacular variety of exquisitely preserved fossils that record the early diversification of animal life. Since the discovery of the first specimens in 1984, many thousands of fossils have been collected, exceptionally preserving not just the shells and carapaces of the animals, but also their soft tissues in fine detail. This special preservation has produced fossils of rare beauty; they are also of outstanding scientific importance as sources of evidence about the origins of animal groups that have sustained global biodiversity to the present day.

Much of the scientific documentation of the Chengjiang biota is in Chinese, and the first edition of this book was the first in English to provide fossil enthusiasts with a comprehensive overview of the fauna. The second edition has been fully updated and includes a new chapter on other exceptionally preserved fossils of Cambrian age, exciting new fossil finds from Chengjiang, and a phylogenetic framework for the biota. Displaying some 250 figures of marvelous specimens, this book presents to professional and amateur paleontologists, and all those fascinated by evolutionary biology, the aesthetic and scientific quality of the Chengjiang fossils.

Hou Xian-guang is former Director, Key Laboratory for Palaeobiology, Yunnan University, Kunming

David J. Siveter is Professor Emeritus of Paleontology, University of Leicester

Derek J. Siveter is Professor Emeritus of Earth Sciences, University of Oxford

Richard J. Aldridge was Professor Emeritus and F.W. Bennett Professor of Geology, University of Leicester

Cong Pei-yun is Professor of Paleobiology, Yunnan University, Kunming

Sarah E. Gabbott is Professor of Paleobiology, University of Leicester

Ma Xiao-ya is Professor of Paleobiology, Yunnan University, Kunming, and the Natural History Museum, London

Mark A. Purnell is Professor of Paleobiology, University of Leicester

Mark Williams is Professor of Paleobiology, University of Leicester

Foreword ix

Preface xi

Part One Geological and Evolutionary Setting of the Biota 1

1 Geological time and the evolution of early life on Earth 3

2 The evolutionary significance of the Chengjiang biota 7

3 The discovery and study of the Chengjiang Lagerstätte 12

4 The distribution and geological setting of the Chengjiang Lagerstätte 20

5 The taphonomy and preservation of the Chengjiang fossils 26

6 The paleoecology of the Chengjiang biota 30

7 Cambrian Lagerstätten 35s

Part Two Chengjiang Fossils 39

8 Algae 40

Fuxianospira gyrata Chen& Zhou, 1997 40

Megaspirellus houi Chen& Erdtmann, 1991 42

Sinocylindra yunnanensis Chen& Erdtmann, 1991 44

Yuknessia sp. of Chen& Erdtmann, 1991 46

9 Ctenophora 48

Galeactena hemispherica Ou et al., 2015 49

Maotianoascus octonarius Chen& Zhou, 1997 50

Batofasciculus ramificans Hou et al., 1999 52

Yunnanoascus haikouensis Hu et al., 2007 54

10 Porifera 56

Paradiagoniella xiaolantianensis Chen et al., 2014 56

Triticispongia diagonata Mehl& Reitner, 1993 58

Saetaspongia densa Mehl& Reitner, 1993 60

Leptomitus teretiusculus Chen et al., 1989 62

Choiaella radiata Rigby& Hou, 1995 64

Choia xiaolantianensis Hou et al., 1999 66

Allantospongia mica Rigby& Hou, 1995 68

Leptomitella conica Chen et al., 1989 70

Paraleptomitella dictyodroma Chen et al., 1989 72

Paraleptomitella globula Chen et al., 1989 74

Quadrolaminiella diagonalis Chen et al., 1990 76

11 Cnidaria 78

Archisaccophyllia kunmingensis Hou et al., 2005 78

Xianguangia sinica Chen& Erdtmann, 1991 80

12 Entoprocta 82

Cotyledion tylodes Luo& Hu, 1999 82

13 Phoronida 84

Iotuba chengjiangensis Chen& Zhou, 1997 84

14 Brachiopoda 86

Yuganotheca elegans Zhang et al., 2014 86

Heliomedusa orienta Sun& Hou, 1987 88

Longtancunella chengjiangensis Hou et al., 1999 90

Diandongia pista Rong, 1974 92

Lingulellotreta malongensis (Rong, 1974) 94

Lingulella chengjiangensis Jin et al., 1993 96

15 Annelida 98

Cambrosipunculus tentaculatus Huang et al., 2004 99

Maotianchaeta fuxianella Chen, 2004 100

16 Trochozoa of uncertain affinity 102

Ambrolinevitus maximus Jiang, 1982 103

Ambrolinevitus ventricosus Qian, 1978 104

Burithes yunnanensis Hou et al., 1999 106

Linevitus opimus Yu, 1974 108

Nectocaris pteryx Conway Morris, 1976 110

Wiwaxia papilio Zhang et al., 2015 112

17 Priapulida and relatives 114

Mafangscolex sinensis (Hou& Sun, 1988) 114

Maotianshania cylindrica Sun& Hou, 1987 116

Cricocosmia jinningensis Hou& Sun, 1988 118

Paraselkirkia sinica (Luo& Hou, 1999) 120

Corynetis brevis Luo& Hu, 1999 122

Sicyophorus rarus Luo& Hu, 1999 124

Palaeopriapulites parvus Hou et al., 1999 126

Eximipriapulus globocaudatus Ma et al., 2014 128

Xiaoheiqingella peculiaris Hu, 2002 130

Omnidens amplus Hou et al., 2006 132

Acosmia maotiania Chen& Zhou, 1997 134

Archotuba elongata (Luo& Hou, 1999) 136

18 Lobopodians 138

Paucipodia inermis Chen et al., 1995 138

Diania cactiformis Liu et al., 2011 140

Microdictyon sinicum Chen et al., 1989 142

Onychodictyon ferox Hou et al., 1991 144

Cardiodictyon catenulum Hou et al., 1991 146

Hallucigenia fortis Hou& Bergström, 1995 148

Luolishania longicruris Hou& Chen, 1989 150

Antennacanthopodia gracilis Ou& Shu, 2011 152

19 Anomalocaridids 154

Anomalocaris saron Hou et al., 1995 154

Amplectobelua symbrachiata Hou et al., 1995 156

Lyrarapax unguispinus Cong et al., 2014 158

Cucumericrus decoratus Hou et al., 1995 160

20 Euarthropoda 162

Isoxys paradoxus Hou, 1987 163

Isoxys auritus (Jiang, 1982) 164

Pectocaris spatiosa Hou, 1999 166

Shankouia zhenghei Chen et al., 2004 168

Chengjiangocaris longiformis Hou& Bergström, 1991 170

Fuxianhuia protensa Hou, 1987 172

Pseudoiulia cambriensis Hou& Bergström, 1998 174

Fortiforceps foliosa Hou& Bergström, 1997 176

Occacaris oviformis Hou, 1999 178

Forfexicaris valida Hou, 1999 180

Jianfengia multisegmentalis Hou, 1987 182

Tanglangia longicaudata Luo& Hu, 1999 184

Parapeytoia yunnanensis Hou et al., 1995 186

Haikoucaris ercaiensis Chen et al., 2004 188

Alalcomenaeus sp. of Tanaka et al., 2013 190

Leanchoilia illecebrosa (Hou, 1987) 192

Retifacies abnormalis Hou et al., 1989 194

Pygmaclypeatus daziensis Zhang et al., 2000 196

Squamacula clypeata Hou& Bergström, 1997 198

Urokodia aequalis Hou et al., 1989 200

Sinoburius lunaris Hou et al., 1991 202

Acanthomeridion serratum Hou et al., 1989 204

Cindarella eucalla Chen et al., 1996 206

Xandarella spectaculum Hou et al., 1991 208

Skioldia aldna Hou& Bergström, 1997 210

Saperion glumaceum Hou et al., 1991 212

Kuamaia lata Hou, 1987 214

Naraoia spinosa Zhang& Hou, 1985 216

Misszhouia longicaudata (Zhang& Hou, 1985) 218

Eoredlichia intermedia (Lu, 1940) 220

Kuanyangia sp. of Hou& Bergström, 1997 222

Yunnanocephalus yunnanensis (Mansuy, 1912) 224

Parapaleomerus sinensis Hou et al., 1999 226

Kwanyinaspis maotianshanensis Zhang& Shu, 2005 227

Kunmingella douvillei (Mansuy, 1912) 228

Kunyangella cheni Huo, 1965 230

Primicaris larvaformis Zhang et al., 2003 232

Branchiocaris? yunnanensis Hou, 1987 234

Canadaspis laevigata (Hou& Bergström, 1991) 236

Chuandianella ovata (Lee, 1975) 238

Clypecaris pteroidea Hou, 1999 240

Combinivalvula chengjiangensis Hou, 1987 242

Synophalos xynos Hou et al., 2009 244

Yunnanocaris megista Hou, 1999 246

21 Chaetognatha 248

Protosagitta spinosa Hu, 2002 248

22 Hemichordata 250

Galeaplumosus abilus Hou et al., 2011 251

23 Ambulacraria of uncertain affinity 252

Rotadiscus grandis Sun& Hou, 1987 253

Eldonia eumorpha (Sun& Hou, 1987) 254

Phlogites longus Luo& Hu, 1999 256

24 Chordata 258

Shankouclava anningense Chen et al., 2003 258

Myllokunmingia fengjiaoa Shu et al., 1999 260

Zhongxiniscus intermedius Luo& Hu, 2001 262

Cathaymyrus haikouensis Luo& Hu, 2001 263

25 Bilateria of uncertain affinity 264

Dinomischus venustus Chen et al., 1989 264

Facivermis yunnanicus Hou& Chen, 1989 266

Vetulocystis catenata Shu et al., 2004 268

Yunnanozoon lividum Hou et al., 1991 270

26 Vetulicolians 272

Heteromorphus confusus (Chen& Zhou, 1997) 272

Pomatrum ventralis Luo& Hu, 1999 274

Yuyuanozoon magnificissimi Chen et al., 2003 276

Beidazoon venustum Shu, 2005 278

Vetulicola cuneata Hou, 1987 280

27 Animals of uncertain affinity 282

Nidelric pugio Hou et al., 2014 282

Allonnia phrixothrix Bengtson& Hou, 2001 284

Stromatoveris psygmoglena Shu et al., 2006 286

28 Species recorded from the Chengjiang biota 288

29 Phylogenetic arrangement of chapters 292

References 293

Systematic Index 308

General Index 312